Field of the Invention
The present disclosure relates to a pipeline structure of a buried pipeline and a program for designing the pipeline structure. Particularly, the present disclosure relates to the technique for achieving a pipeline structure that allows suppression of cracks, breakage and the like of a pipeline by following a large ground displacement (fault displacement) caused by the movement of a fault.
Description of the Background Art
Pipelines for supplying water, gas and the like are placed in various places. Each of these pipelines includes a plurality of pipes that are connected by joints. For example, Japanese Patent Laying-Open No. 2010-261468 and Japanese Patent Laying-Open No. 2004-232679 describe a so-called earthquake-resistant joint in which a joint portion extends/retracts and flexes to follow the movement of a ground caused by an earthquake and the like in order to maintain the function of a pipeline.
The pipeline is sometimes buried in a region having an active fault and the like where a large ground displacement is expected to occur. In the place having a fault, an amount of ground displacement is sometimes several meters due to the movement of the fault such as a normal fault, a reverse fault or strike slip. Therefore, it is impossible to obtain the extension/retraction and flexion functions that can deal with this large ground displacement, simply by using the conventional earthquake-resistant joint as described in the aforementioned patent documents, and it may become difficult that the pipeline functions as a lifeline. Thus, in order to allow the pipeline to deal with the large ground displacement, various techniques are under study. For example, Japanese Patent Laying-Open No. 2006-70994 describes a detachment preventive joint in which a joint that connects pipes has enhanced flexion function (bending capability).